If you need more space in your home, you’ve likely asked yourself the big question: should you build a home extension or convert your loft? Both options can add space and value — but which one offers the better return for UK homeowners?
At Buildaway, we’ve managed hundreds of extensions and loft-style builds across London, Kent, and Essex. Here’s a breakdown of the pros, cons, and real-world value of each approach — to help you make the right choice for your property and budget.
1. What Is a Home Extension?
A home extension typically adds space at ground level, such as:
- Rear kitchen extension
- Side return extension
- Wraparound ground floor build
- Two-storey additions
This option increases your overall footprint and allows for completely new layouts — from larger kitchens to extra bedrooms or open-plan living spaces.
2. What Is a Loft Conversion?
A loft conversion transforms unused roof space into a liveable area. This could be:
- A master bedroom with en-suite
- A home office or study
- An additional lounge or guest room
Most homes with a pitched roof have the potential for a loft conversion, though the style of roof and existing height will impact feasibility.
3. Cost Comparison
Here’s a rough guide to average costs in London and the South East:
- Loft conversion: £35,000 – £65,000
- Single-storey extension: £50,000 – £90,000+
Loft conversions are generally cheaper because they make use of an existing structure. Extensions tend to cost more due to groundwork, foundations, and external construction.
4. Value Added to Your Property
According to UK property data:
- Loft conversions can increase property value by 15–20%
- Extensions can boost value by 20–25% (depending on size and finish)
Extensions usually add more value — especially if they expand kitchen or living areas — but lofts still deliver a strong return on investment.
5. Planning Permission & Regulations
Many loft conversions fall under permitted development, meaning no formal planning application is needed (though Building Regulations still apply).
Extensions, especially rear or wraparound builds, often require full planning approval — which adds time and admin.
At Buildaway, we help manage planning, drawings, and compliance for both options, so you’re never left chasing paperwork.
6. Disruption During Build
- Loft conversions tend to be less disruptive and quicker to complete (8–12 weeks)
- Extensions involve more structural work and site access (10–16+ weeks)
If your family is living at home during the project, a loft may cause less day-to-day interruption — especially if scaffolding can be used externally.
7. Space and Lifestyle Considerations
Extensions are ideal when you want to expand shared family space, open up kitchens, or build multi-functional rooms on the ground floor.
Loft conversions are perfect for adding a quiet, private room — often used for a master suite, teenager’s bedroom, or remote working space.
Your property layout and lifestyle needs should guide your decision.
Which Option Is Right for You?
Here’s a quick summary:
- Choose a loft conversion if you want extra bedrooms or home office space with minimal disruption and lower costs.
- Choose an extension if you want to expand your kitchen or living space and add maximum value to your home.
Not sure what your property allows? Buildaway can assess your home and advise on the most cost-effective and practical route forward.